Had my plenums off today to do the valve cover gaskets. First time I've had them off since I bought it. There was a layer of oil all over the inside of the upper and lower plenum and the intake manifold. I looked in the intake pipe and there was some at the very end where it attaches to the throttle bottle. Looked like maybe it was coming in from the vacuum line that attaches right there.
Any thoughts on what this could be or what things I should be looking at? I replaced the PCV valve today when I had the valve covers off but the old one didn't seem like it had failed.
Also, is there a product I can use to clean the the oil out of the intake without having to take it off the car?
My experience with German autos is they come with one, they give it a fancier name, Oil/Air Separator. Some autos need them more than others, especially GDI engines of which ours are far from it, so as alumarine said, nbd, in these type engines.
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2001 Limited 4WD - 346+K - SunfireRed\Thunder Cloud; - 265/75/16 Michelin A/T2s - Fat Pat's 1.5" BL - StopTech ANGLED rotors - In series 699 trans cooler, New Yota1 transmission, All new OEM suspension front to rear.
My experience with German autos is they come with one, they give it a fancier name, Oil/Air Separator. Some autos need them more than others, especially GDI engines of which ours are far from it, so as alumarine said, nbd, in these type engines.
Yes, a catch can would be the way to keep your intake cleaner from oil blow-by. And, we have a video on how to install one.
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__________________ "My old man is a television repairman, he's got this ultimate set of tools. I can fix it!"
How many miles does it have? Over time, the rings wear, and more compression leaks into the crankcase and has to come out viat that PCV system. The higher the volume, the faster it moves, and the less effective the oil/air separators get, to the point where more oil gets into the intake.
It's not even particularly a huge problem then either, up until it gets so bad that it starts smoking out the tail pipe and clogging the cat. Or need a quart of oil added every 500 miles.
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'99 Highlander 5-spd manual e-locker no-running-board
SS 3" suspension lift/1" body lift/33" tires/'Snowflake' TRD Taco wheels/231mm Tundra brakes/bumpers/armor/sliders/winch/Sherpa Matterhorn rack
Manual front hubs, NWF Eco-crawler transfer case doubler, second gas tank
How many miles does it have? Over time, the rings wear, and more compression leaks into the crankcase and has to come out viat that PCV system. The higher the volume, the faster it moves, and the less effective the oil/air separators get, to the point where more oil gets into the intake.
It's not even particularly a huge problem then either, up until it gets so bad that it starts smoking out the tail pipe and clogging the cat. Or need a quart of oil added every 500 miles.
I'm just over 260K on the odometer. The exhaust never smokes and it uses maybe a half quart every 5000 miles or so.
I was more concerned with potential carbon build up on the valves but I guess because this isn't a direct injection engine the fuel spray should be keeping the valves pretty clean.
Yeah, no worries. Check back in after another 260K miles, lol.
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'99 Highlander 5-spd manual e-locker no-running-board
SS 3" suspension lift/1" body lift/33" tires/'Snowflake' TRD Taco wheels/231mm Tundra brakes/bumpers/armor/sliders/winch/Sherpa Matterhorn rack
Manual front hubs, NWF Eco-crawler transfer case doubler, second gas tank
GM makes a foaming upper engine cleaner that I’ve used often decarboning my old 96 Saturn SL1. Sadly the can recommends spraying through the throttle body which won’t work with air not flowing through the MAF sensor. Or mine won’t run with the inlet tube removed.
It’s just the condensing oil vapor you see from the PCV system.
I never considered a catch can on a non direct injection engine.
Even older BMW, Porsche, Audi and MBs come with one from the factory standard, much larger than the example I posted, they're Serious about it for a reason.
Interestingly enough, Kia/Hyundai GDIs don't come with one and they suffer for it.
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2001 Limited 4WD - 346+K - SunfireRed\Thunder Cloud; - 265/75/16 Michelin A/T2s - Fat Pat's 1.5" BL - StopTech ANGLED rotors - In series 699 trans cooler, New Yota1 transmission, All new OEM suspension front to rear.
Even older BMW, Porsche, Audi and MBs come with one from the factory standard, much larger than the example I posted, they're Serious about it for a reason.
Interestingly enough, Kia/Hyundai GDIs don't come with one and they suffer for it.
My 2008 A4 didn't have a catch can but had an "oil separator" system integrated into the valve cover. It didn't work worth a damn though. Part of my "regular maintenance" was taking the intercooler pipes off and dumping out about 4 oz of oil at every oil change. It didn't leak a drop onto the ground but it burned up a quart every 1200 miles. I suspect that car also had bad oil control rings which likely contributed to the problem.
My 2008 A4 didn't have a catch can but had an "oil separator" system integrated into the valve cover. It didn't work worth a damn though. Part of my "regular maintenance" was taking the intercooler pipes off and dumping out about 4 oz of oil at every oil change. It didn't leak a drop onto the ground but it burned up a quart every 1200 miles. I suspect that car also had bad oil control rings which likely contributed to the problem.
I also did a catch can back in 2020, can confirm it does catch stuff. each oil change about 2-3 ounces of black goo get cleaned out. Not a lot but stuff does get pushed out the PCV path.
I was never really concerned about the PCV valve venting into the intake that will coat the plenums with oil.. The last valve pan cover gasket job i did. I just cleaned them out with brake cleaner.
If your going to clean in front of your intake throttle body, you really have to be careful not to jack up the IAC valve that controls your idle. Many years ago I thought I would just clean that off with brake cleaner while the engine was running ( well after a week, my idle was working properly again) So I do not recommend that as I was lucky i didn't have to rebuild and clean the IAC out. :-(